a = [11, 22, 33, 44, 11, 22, 33]

print(a)

b = []

for i in a:
    if i not in b:
        b.append(i)

print(b) # [11, 22, 33, 44]  重复中没有添加进去

print(set(a)) # {33, 11, 44, 22}  TODO 为什么是这样的顺序

print((list(b))) # [11, 22, 33, 44]